asio_net

a tiny C++14 Async TCP/UDP/RPC/DDS library based on asio and rpc_core

Features

• Header-Only
• TCP/UDP: support auto_pack option for tcp
• RPC: via socket/SSL, domain socket, support c++20 coroutine for asynchronous operations
• DDS: via socket/SSL, domain socket
• Service Discovery: based on UDP multicast
• IPv4 and IPv6
• SSL/TLS: depend OpenSSL
• Serial Port
• Automatic reconnection
• Comprehensive unittests

Options:

• TCP can be configured to automatically handle the problem of packet fragmentation to support the transmission of complete data packets.

• Supports setting the maximum packet length, and will automatically disconnect if exceeded.

Requirements

• C++14
• asio
• Optional: C++20 (for rpc coroutine api, co_await async_call)

Usage

• clone

git clone --recurse-submodules [email protected]:shuai132/asio_net.git

or

git clone [email protected]:shuai132/asio_net.git && cd asio_net
git submodule update --init --recursive

The following are examples of using each module. For complete unit tests, please refer to the source code: test

• TCP

  You can enable automatic handling of packet fragmentation using tcp_config. Subsequent send and receive will be complete data packets.

  By default, this feature is disabled.

  // echo server
  asio::io_context context;
  tcp_server server(context, PORT/*, tcp_config*/);
  server.on_session = [](const std::weak_ptr<tcp_session>& ws) {
    auto session = ws.lock();
    session->on_close = [] {
    };
    session->on_data = [ws](std::string data) {
      ws.lock()->send(std::move(data));
    };
  };
  server.start(true);

  // echo client
  asio::io_context context;
  tcp_client client(context/*, tcp_config*/);
  client.on_data = [](const std::string& data) {
  };
  client.on_close = [] {
  };
  client.open("localhost", PORT);
  client.run();

• UDP

  // server
  asio::io_context context;
  udp_server server(context, PORT);
  server.on_data = [](uint8_t* data, size_t size, const udp::endpoint& from) {
  };
  server.start();

  // client
  asio::io_context context;
  udp_client client(context);
  auto endpoint = udp::endpoint(asio::ip::address_v4::from_string("127.0.0.1"), PORT);
  client.send_to("hello", endpoint);
  context.run();

• RPC

  rpc based on tcp and rpc_core, and also support ipv6 and ssl. more usages, see rpc.cpp and rpc_config.cpp

  // server
  asio::io_context context;
  rpc_server server(context, PORT/*, rpc_config*/);
  server.on_session = [](const std::weak_ptr<rpc_session>& rs) {
    auto session = rs.lock();
    session->on_close = [] {
    };
    session->rpc->subscribe("cmd", [](const std::string& data) -> std::string {
      return "world";
    });
  };
  server.start(true);

  // client
  asio::io_context context;
  rpc_client client(context/*, rpc_config*/);
  client.on_open = [](const std::shared_ptr<rpc_core::rpc>& rpc) {
    rpc->cmd("cmd")
        ->msg(std::string("hello"))
        ->rsp([](const std::string& data) {
        })
        ->call();
  };
  client.on_close = [] {
  };
  client.open("localhost", PORT);
  client.run();

and you can use C++20 coroutine:

  // server
  rpc->subscribe("cmd", [&](request_response<std::string, std::string> rr) -> asio::awaitable<void> {
    assert(rr->req == "hello");
    asio::steady_timer timer(context);
    timer.expires_after(std::chrono::seconds(1));
    co_await timer.async_wait();
    rr->rsp("world");
  }, scheduler_asio_coroutine);

  // client
  // use C++20 co_await with asio, or you can use custom async implementation, and co_await it!
  auto rsp = co_await rpc->cmd("cmd")->msg(std::string("hello"))->async_call<std::string>();
  assert(rsp.data == "world");

Inspect the code for more details: rpc_s_coroutine.cpp and rpc_c_coroutine.cpp

• DDS

  // run a server as daemon
  asio::io_context context;
  dds_server server(context, PORT);
  server.start(true);

  // client
  asio::io_context context;
  dds_client client(context);
  client.open("localhost", PORT);
  client.subscribe("topic", [](const std::string& data) {
  });
  client.publish("topic", "string/binary");
  client.run();

• Server Discovery

  // receiver
  asio::io_context context;
  server_discovery::receiver receiver(context, [](const std::string& name, const std::string& message) {
    printf("receive: name: %s, message: %s\n", name.c_str(), message.c_str());
  });
  context.run();

  // sender
  asio::io_context context;
  server_discovery::sender sender_ip(context, "ip", "message");
  context.run();

• Serial Port

  asio::io_context context;
  serial_port serial(context);
  serial.on_open = [&] {
    /// set_option
    serial.set_option(asio::serial_port::baud_rate(115200));
    serial.set_option(asio::serial_port::flow_control(asio::serial_port::flow_control::none));
    serial.set_option(asio::serial_port::parity(asio::serial_port::parity::none));
    serial.set_option(asio::serial_port::stop_bits(asio::serial_port::stop_bits::one));
    serial.set_option(asio::serial_port::character_size(asio::serial_port::character_size(8)));

    /// test
    serial.send("hello world");
  };
  serial.on_data = [](const std::string& data) {
  };
  serial.on_open_failed = [](std::error_code ec) {
  };
  serial.on_close = [] {
  };
  serial.open("/dev/tty.usbserial-xx");
  serial.run();

Links

• RPC library for MCU

  most MCU not support asio, there is a library can be ported easily: esp_rpc